Electrical protective device.



J. N. MAHONEY. ELECTRICAL PROTECTIVE DEVICE. APPLICATION FLLED JULY 3.19! &

Patented Dec. 1?, 1918.

W X TN UNITED STATES PATENT oninon.

JOSEPH-N. MAHONE Y, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR 'IO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

ELECTRICAL PBOTECTIVE DEVICE.

Specification of Letters Patent.

Patented-Deena, 1918.

To all'whom it may concern:

Be it known that I, JOSEPH N. MAHONEY, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Protective Devices, of which the following is a specification.

My invention relates to electrical protective devices and particularly to relay mechanisms that are employed for tripping circuit ihterrupters upon the occurrence of predetermined circuit conditions.

One object of my invention is to provide a simple and economical relay system of the character indicated that may be operated. by current derived from the circuit in connection with which the interrupter is employed, thereby obviating the necessity of employing a separate source of energy for supplying the operating current for its trip coil.

Another object of my invention is to provide a system of the above indicated charac: ter that shall have means for connecting the. trip coil in operative relation to the main circuit only when the relay has functioned properly. v

The usual method of supplying a trip coil with energy from the circuit to which its inconnected to the transformer 4 that it is responsive to predetermined conditions in the circuit 1. That is, it may be adapted to operate upon the occurrence of an overload or the reversal of energy in the circuit 1 operation.

and may be delayed or not in its time of One t-ermmal of the winding 8 of-the re- I lay 5 is connected to one terminal of the transformer 4 and its other terminal isconnected to one terminal of a reactor 12 and to the movable contact member 11. The other terminal of the reactor 12 is connected to one terminal of the winding 13 of an electromagnetically operated switch 14 the other terminal of which is connected to the stationary contact member 10. The terminal of the. winding 13 that is connected to the reactor 1:2 is also connected to a movable contact member 15 which is adapted to be actuated by the movable .member 16 of the switch 14. The movable contact member 15 is adapted to engage two stationary contact members 17 and 18 and is of such form and.

operatively connected to one terminal of the terrupter is connected is to cause the relay contact members to serve as the separable terminals of a shunt connection that is'connected across the terminals of the trip coil. However, with this arrangement, it has been foundthat frequently, upon the occurrence of an overload, because of imperfect con tacts, the interrupter tripped before the re lay functioned properly. In view ofthis, provide means whereby the trip coil is, switched into the circuit by an electromagnetic device that is controlled by the. relay, and I provide also means for maintaining a substantially constant potential across the electromagnetic device after the relay operates.

The single figure of the accompanying drawing is a digrammaticview of a distributing system embodying my invention.

An electric circuit 1 is provided with an interrupter 2 having a trip coil 3 and a series transformer that is adapted to supply the trip coil 3 with energy. A relay 5, comprising a magnetizabie core member 6, windings 7 and 8, an armature 9 and contact members 10' and 11, adapted to be so transformer. a and to one terminal of the winding of the trip coil 3, the other terminal of whichis connected to the stationary contact member 18.

Under normal conditions, current proportional to the current that traverses the circuit 1 traverses the winding 8 of the relay 5, the reactor 12 and contact memberslo and 17. This current is not suthcient to operate the relay 5, but, when an overload traverses the circuit 1, sutiicient current traverses the winding 8 to efiect engagement of the contact members 10 and 11. This permits current to traverse the winding 13 of the switch it, thuscaiising the movable contact member 15 to engage the stationary contact member 18. When the contact members 15 and 18 are in engagament, the trip coil 3 is connected in series relation with the transformer 4 and the windings 8 and 13. Thus, current proportional to the current traversing the circuit 1 will. traverse the trip coil 3 from the circuit to cause the interrupter 2 to be tripped.

The reactor 12 is provided with c member 19 that is adapted to. become satu rated when a current ofgreater volume than that required to operate the switch tr v erses the circuit, and, consequently, the rethereacross after therelay 5 has functioned.

When the circuit interrupter 2' opens, no current will -traverse, the winding 8 and, consequently, the contact members 10 and llwill be disengaged, themovable contact member of the switch 14 willmove into engagement ,1 with the stationary contact member l7 jand ,the'devices will be in their operative"positions when the circuit inter- 'rupter Zis again'closed. I i 1 5 I do not limit my invention to the par ,p ticular' arrangement and devices illustrated,

as it may be variously modified without departing:- from the spirit and scope 'of'the in vention, as set forth inthe appended claims.

I claim as my invention; v i; 1. In an electric circuit, the'combination with a circuit interrupter and a normally opencircuited trip coil therefor, of a relay operatively connectedto .thecircuit, a magnetically operatedswitchjcontrplled by the relay "for connecting the trip coil in opera- *tive relation to the circuit, andmeans for causing the'potential across the Winding of said switch to remain substantially constant when it is energized;

p '2. In aneIectri'c-circuit, witha circuit interrupter and a normally open-circuitedtrip coil the-reforf,',of a'relay operatively connected. to the circuit, and

electromagnetic means connected in series with the Winding ofthe'relay for connecting the trip coil in series with the winding of the relay without open circuiting the re lay winding and a reactor formaintaining 40 the potential across the electromagnetic means constant when the relay operates. 3. In an electric. circuit, the combination with a circuit interrupter and a trip coiltherefor,0f a relay operatively' connected to the c1rcuit,;an electromagnetic deuce controlled by the relay for connecting the trip the combination coil in series with the relay, and means for maintaining the potential across the electromagnetic device substantially constant when i it is energized,

4. In an electric circuit, the combination tially constant when it is energized.

5. In an electric circuit, the combination with a circuit, interrupter and a trip coil therefor, of a relay operatively connected to ed to be connected. in series with the relay 'when-it'operates andfadapted'to connect the trip e011 also in series with the relay, and means for maintaining the potential across the electromagnetic device substantially constant after the relay operates.

6. In an electric circuit, the combination with a circuit interrupter. and a trip coil therefor, of a relay operatively connected to the circuit, an electromagnetic device controlled by the relay for connecting the trip coil in series with the relay, and an imped- H ancedevice for causing-the potential across the electromagnetic device to be substantially constant when it is energized.

'7. In an electric circuit, the combination .the circuit, an electromagnetic device adaptwith a circuit interrupter and a trip coil therefor, of a relay operatively connected to the circuit, an electromagnetic device controlled by the relay for connecting the trip coil in series with therelay, and an. imped-v ance device for causing the potential across the electromagnetic device to be substantially constant after the relay operates.

, In testimony whereof, I have hereunto subscribed my name this 15th day of June,

JOSEPH N. MAHONEY. 

